This article treats the various forms of adjustment between scientific and religious discourses at school. It aims to analyse the beliefs and practices of schoolmasters and to explore how the oppositions between the "dominant" discourses of Western science and those of religion are addressed in secondary education in Senegal. The analysis leans on the Actor-Network-Theory and the concept of "apparatus" from Foucault. The article shows that, in the secular Republic of Senegal, contradictory messages on some sensitive issues are conveyed to pupils, in the classroom, by the official schoolmaster himself. The schoolmasters, whatever their religion, teach "for" religion in public schools (in a devotional sense); they do not teach "about" religion (in an academic sense). An "enrolment" work is in progress in the official schools whereby pupils adhere to the "true" religious discourse, challenged by the "true" scientific discourse. The schoolmasters do not want to exclude the official curriculum but wish to teach religious knowledge. The State cannot limit each discourse to its own sphere of relevance and fails to impose its criteria on some actors who prefer those offered by their own religious networks. A Senegalese "national religious apparatus" produces effects on schoolmasters' educational practices and curriculum.